j^. Natl KAi. IIiskkv Bui.i.etin. 



the inayt. The hoisliiii;- machine was placed aliout six feet in 

 front of tile mainmast. The iron rope led from the reelino- 

 drum to a twelve-inch iron block fastened to the centre of the 

 deck just aft of the gallev. thence to a similar block hooked 

 to the ends of the dredging- spar, and then overboard. When 

 in use the spar is guyed fore and aft so as to be practically im- 

 movable. These gu\'s should be sufilciently strong to bear 

 the entire strain of the dredge line. Indeed, great strength 

 is necessarv in all parts of the equipment when a sail-vessel is 

 used, as it is impossible to back, and the strain is something- 

 terrible when the dredge suddenly fouls. This strain could 

 doubtless be materiallv lessened by the use of some sort of 

 accumulator, such as was used on the " Blake. "^ This does 

 not seem to be an actual necessity, however, for. as /Mexander 

 Agassiz sa\s. "the curve made by the wire rope, as it leads 

 from the vessel to the trawl, is of itself the best accunnilator. 

 as a comparative! V slight strain will constantly tend to change 

 the form of the catenary." With the primitive dredging 

 equipment used bv us. it is necessary for some one to guide 

 the line so that it will coil properly in reeling in under tension. 

 Our means of doing this was crude, but effective, consisting 

 of a strip of inch plank about four feet long, provided with a 

 slot through which the rope ran. by v^'hich it was kept from 

 slipping horizontallv. The end of the board was placed on 

 the deck, and leverage exerted to the right or left, as the 

 reehng demanded. 



^ Each dav. when the dredge, trawl, or tangles were let 

 down for the tirst haul, the entire length of the iron rope 

 w^as oiled by hand, hi addition to this, the whole coil was 

 thv>roughly sopped with oil whenever it was dry. 



In addition to the trawls, dredges, and tangles a number of 

 simple appliances were provided for surface and shoal w^ater 

 collecting. Convenient and cheap dip nets can be secured by 

 purchasing crab nets at any sea-port, and replacing the net by 

 silk bolting cloth, cheese cloth, or mosquito netting, thus 

 securing a series of netting from the finest to a suHicientK' 



' .\iiiissi/.. "'I'hree Cruisi's of tin- • Ulakf."'" piii^e \i. 



